1. Field of the Invention
The present invention relates to a method of manufacturing ceramic electronic components such as ceramic parts, laminated ceramic capacitors, LC filters, and composite high-frequency electronic components. The method uses a computer-controlled ink-jet apparatus, which jets ink to form the foregoing various electronic components on non-contact basis.
Further, the present invention enables a computer-controlled ink jet apparatus to form a high-precision pattern with least oozing and dropping of ink on the surface of low ink acceptability, such as metal surface. Also on the surface of a three-dimensional substance, a high-precision pattern can be formed. Furthermore, on the surface of a metal pipe, for example, which exhibits low ink acceptability and three-dimensional, a high-precision pattern can be formed with least oozing and dripping. An ink pattern provided in accordance with the present invention can also be used for an etching resist. So, it can be used for manufacturing printers' magnet rolls and the like various types of electronic components.
2. Background Art
A conventional method of manufacturing various ceramic electronic components, first of all, prints a predetermined electrode pattern on an unbaked ceramic member such as a green sheet of ceramic by, e.g., screen printing. Next, laminate the ceramic green sheets on which the electrode patterns are printed, then cut the laminated sheet in a given shape, and bake them. Finally form external electrodes. Another method forms conductive or insulating patterns on an unbaked ceramic member, then bake the member.
A conventional printing method such as a screen printing can form electrodes in an identical shape; however, it is not good at forming electrodes of different patterns, i.e., small batches of a variety of products, or forming electrodes on non-contact basis, or forming electrodes at a high speed. Japanese Patent Application Non-examined Publication No. 2000-327964 and No. 2000-182889 disclose methods of manufacturing electronic components using inkjet for overcoming the foregoing problems. However, forming an electrode pattern using inkjet depends on surface condition of a substrate on which the pattern is to be printed. Thus some ceramic green sheet repels water or oil of ink, which produces non-uniform thickness of the printed pattern. As a result, a desirable electrode pattern cannot be formed.
Problems of ink acceptability of those substrates to be printed are described with reference to FIG. 11. FIG. 11A and FIG. 11B show an electrode-shape required as a ceramic electronic component. Electrode pattern 1 shown in FIG. 11A has no pin-hole therein, and is required to have a uniform thickness and to be a highly accurate fine pattern. Therefore, in FIG. 11B, electrode pattern 1 is formed on a ceramic green sheet on base film 2 in a uniform thickness.
FIG. 11C illustrates an electrode pattern formed with conventional inkjet. As shown in FIG. 11C, the electrode patterns formed with inkjet on the ceramic green sheet are deformed due to repelling the jetted ink on the surface because the ceramic green sheet does not have ink acceptability. FIG. 11D is a sectional view of FIG. 11C and shows a cross section of the electrode patterns formed with the conventional inkjet. As shown in FIG. 11C and FIG. 11D, electrode patterns 4 are repelled and deformed, which is caused by poor wetness, namely, low ink-acceptability of the ceramic green sheet on which patterns are to be printed. This is a similar phenomenon as a water drop is repelled on a base substrate which has been processed to repel water and oil. If such an ink-repellant phenomenon occurs in an electrode pattern, pinhole 5 tends to be formed inside electrode pattern 4. As a result, repelled electrode pattern 4 ends up having non-uniform thickness.
As such, jetted ink landed on the surface of the substrate is deformed as shown in FIG. 11C and FIG. 11D because the viscosity of the ink is as low as 0.01-0.1 poise and extremely subjected to surface tension of the substrate on which patterns are to be printed. Thus the landed ink is deformed before the ink is dried or cured. In the case of screen printing, on the other hand, the viscosity of ink is as high as several hundreds poise, and the ink is hardly deformed. In a case of an inkjet printer using papers available in the consumer market, since landed ink soaks into the paper, such uneven printing does not occur. However, in the case of ceramic electronic component posed in the present invention, if jetted ink soaks into a ceramic green sheet, electrical insulation or reliability of a finished component is sometimes substantially degraded. Quick-drying of landed ink is one of measures against such a problem. However, quick-drying ink tends to dry and harden at a tip of a printer head of an inkjet apparatus, and eventually clogs the printer head. Therefore, it is not good at producing stable print for long hours.
As discussed above, efforts have been made for printing given electrode-patterns accurately using inkjet; however, as shown in FIG. 11C and FIG. 11D, irregular bumps and dips are formed in a sectional view of electrode patterns, thus a required electronic component cannot be produced.
An apparatus that forms a given three-dimensional structure using laser beam is recently commercialized. This apparatus exposes photo-sensitive resin to laser beam and cures the resin, and repeats this operation plural times before forming the given three-dimensional structure. The finished three-dimensional structure is formed of resin, therefore if it is sintered, an electronic component cannot be produced. If an electrode or a member for forming an electronic component such as ceramic is added to this kind of photo-sensitive resin, it becomes difficult to cure this subject with light.
Japanese Patent Application Non-examined Publication No. H02-415702 discloses a method of forming a three-dimensional structure using inkjet. This method deposits a first layer of powder material at a limited area, then deposits binder at a selected area of the powder material layer, so that the bound powder material is formed at the selected area before a component is produced. This method repeats the foregoing operation selected number of times for producing a given plastic component. Thus a successive layer is formed at the selected area of the bound powder material. Then un-bound powder material is removed, whereby a three-dimensional structure is formed. However, in the case of the disclosure discussed above, the inkjet apparatus jets binder for powder, and the binder does not include the powder. When the three-dimensional structure is taken out, surplus powder should be brushed off. Further, this disclosure has difficulty for forming a three-dimensional structure including plural members such as ceramic, electrodes and so on, which are necessary for an electronic component.